九州東シナ海沿岸で副振動災害を引き起こす気象津波の発生機構に関する研究  [in Japanese] STUDY ON GENERATION MECHANISM OF METEOTSUNAMIS CAUSING SECONDARY OSCILLATIONS ON THE COASTS OF KYUSHU ALONG THE EAST CHINA SEA  [in Japanese]

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Abstract

海洋上を進行する微気圧変動の伝搬速度が海洋長波の波速に近づくと,大気・海洋間の共振を引き起こし,発達した海洋長周期波がさらに沿岸地形の固有周期と共振して大きな副振動災害を発生させる.こうした気象擾乱を起因とする長周期波災害は,九州西岸では「あびき」と呼ばれてきたが,最近同様な災害事例が北海・地中海等に面する国から報告され,「気象津波」の呼称が定着しつつある.本研究は,鹿児島県上甑島の浦内湾における気象津波の解明を行うために,2次にわたって実施した現地観測と,中国本土から東シナ海全域の大気場の数値解析および沖合から沿岸部に至る海洋場の数値解析,の3つの結果をとりまとめたもので,気圧擾乱の発生・発達から外洋の長周期波の発達,沿岸域に到達後の湾水振動に至る一連のメカニズムを検討したものである.

 Meteorologically generated large secondary oscillation along coasts of Kyushu has been explained into two stages; long ocean waves induced by air pressure disturbance are amplified by air-sea interactive resonance when both moving speeds nearly coincide, and the arrived long waves are amplified by the geometric resonance with the eigen frequency of the bay or harbor. The area of west Kyushu coasts facing the East China Sea has suffered the seiche disasters locally called “Abiki”. Recently, the same type disasters have been reported from the countries along the Mediterranean, Adriatic and North Sea, etc. The term “Meteotsunami” has become widely recognized and the importance of the subject is increasingly appreciated. We have studied the meteotsunami events at Urauchi Bay in Kamikoshiki Islands, Kagoshima by seasonal field observations in 2010 and 2012. For obtained meteotsunami events, we have numerically analyzed the atmospheric fields over the East China Sea and southeastern China mountains, as well as the oceanic fields from the offshore to the coastal areas. The present study aims to correlate the findings obtained by our field observations and numerical simulations, and to clarify a series of mechanism from the generation of the air pressure disturbance, and its development, resonance with ocean long waves, and amplification in the bay of the arriving long waves.

Journal

  • Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering)

    Journal of Japan Society of Civil Engineers, Ser. B2 (Coastal Engineering) 70(1), 79-96, 2014

    Japan Society of Civil Engineers

Codes

  • NII Article ID (NAID)
    130004691538
  • Text Lang
    JPN
  • ISSN
    1884-2399
  • Data Source
    J-STAGE 
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